Clutch detent



Oct. 28, 1941. R. WENTWORTH ET AL 6 CLUTCH DETENT Filed 001;. 25, '1938FIG. I 23 l6 a9 Y nu I v I 0X I j l n [III I 'fl'rllgllllllllllllllllINVENTORS R. WENTWORTH BY u. DAVIS Patented Oct. 28, 1941 UNITED STATESPATENT OFFICE- CLUTCH DETENT Rollins Wentworth, Verona, N. J., and MaxU.

Davis, Lakewood, Ohio, assignors to The Western Union Telegraph Company,New York, N. Y., a corporation of New York Application October 25, 1928,Serial No. 236,850

4 Claims. (01. 192-24) This invention relates in general to grab orratchet type clutches and more particularly to an attachment or detentfor such types of clutches when employed, for example, on telegraphtransmitting mechanisms wherein a rotatable distribapplication of theinvention is not limited to this particular type of clutch and service,but can be advantageously applied to various other types of clutches andservices where it is desired to have a quick and positive acting clutchwith no slipping of the clutch members from the time the clutch 20 isengaged until it is disengaged.

In telegraph keyboards of the nature with which this inventionespecially is concerned such as, for example, the type similar to thatdisclosed in a patent to H. L. Krum, No. 1,595,472, issued August 10,1926, wherein the depression of any one of a set of key levers causesthe release of a normally at rest transmitting sleeve for one revolutionwhich during its rotation transmits to the line circuit a code group ofimpulses representing according to a predetermined arrangement theactuated key lever. Each of these groups of signals thus transmitted areof the permutation type having a start impulse followed by a group ofeither five or six intelligence impulses and terminated by a restimpulse, making a total of seven or eight separate impulses for eachsignal. The length of duration of the start impulse and the five or sixvariable intelligence impulses are usually the same while the length ofthe rest impulse varies with the frequency with which the groups aretransmitted, its length approaching the length of one of theintelligence impulses as a minimum. The rest impulse is transmittedduring the last part of the revolution of the distributor member andduring the time the memher is at rest. Where there are six intelligenceimpulses in each code group, the distributing member or cam sleeve isdivided into approximately eight equal divisions and in high speedservice where the distributor or keyboard operates at a rate such as,for example, five hundred characters per minute, the period allotted totransmit each separate impulse is obviously of very short duration.Therefore, any slight slippage of the clutch members or any relative.rotative movement of the driven and driving membersduring its operationwill tendto vary the length of some or all of the impulses which, as iswell known to those versed in the art,'has anadverse effect on anassociated receiver or, in the terminology of the art, decreases therange of the receiver or receivers in the circuit. If, for example, theclutch did not fully engage until it had made part of a revolution andwhen it did fully engage allowed the driving member to rotate a smallamount, such as one half the distance between two consecutive teeth onaforty tooth ratchet clutch which would be aboutfive degrees relative tothe driven member, it would cause a lengthening of the impulse beingtransmitted at the time the clutch slipped an. amount equal to about 10%of the length it should be, and as stated above would adversely affectthe operation of associated receiving instruments. Other causes thatcould affect the length of signals transmitted may be due to the suddenengagement of the driven and driving members causing the driven memberto jump ahead of the driving member a tooth or two and thus shorten thelength of the start impulse. w

It is therefore one of the primary objects of the invention to provide adetent or attachment for clutches of the above general type whichprevents substantially all rotation of the driven member until it hasbeen properly engagedwith the driving member. The proper engagementbetween the driven and driving members occurs when a substantial portionor more of the driving surfaces on these members are engaged inoverlapping relation so that substantially all relative rotation ofthese members with respect to one another is prevented.

Another object of the invention is to prevent disengagement of thedriving and driven members during substantially a complete revolutionthereof and thus establish a substantially positive couplingbetween thetwo members during rotation of the driven member.

Still another object of the invention is to provide a detent forclutches of the above general type which when used in conjunction withkeyboards enables the force of the spring tending to move the drivenmember to be reduced, thus enabling the clutch release or throw-outlever'to be more easily operated and consequently require a lighterpressure on the keylevers to trip the clutch.

Other objects of the invention reside in the mitter of the above typecooperating with the in-.

vention and the manner in which the invention is associated therewith;Fig. 2 is a plan view of the elementsof invention and some of thecooperating element s,

of the associated clutch mechanismfemployed on;

the keyboard in their normal rest position L Fig. 3 is a view of theelements shown in Fig. 2

showing the clutch in an operating -position; and' Fig. 4 is a sectionalview taken substantially on line 44 of Fig. 1 showing the distributingmember such .as a transmitting sleeve and the transmitting shaft. 1 Y

Referring first to Fig. '.1,' only the elementslof the keyboardthat'aifect orare affected by the invention or. are thought to benecessary for a complete understanding of th'eoperation of the inventionare shown. The description of the operation of this type of a keyboardis fully given in the above mentioned patent to Krum and in thefollowing paragraphs the description thereof will be limited to theextent to which it cooperates with the elements of the invention. Ingeneral the keyboard comprises a base member II upon and in which areattached and supported the various elements of the keyboard. Pivoted inthe base II and extending horizontally from the front are a series ofkey levers I2 which have on the upturned ends thereof key designatinggrooves 29 and 3I. Formed on the right hand face of the collar 28 are aseries of ratchet teeth 32, Fig. 2, which are in operative relation witha similar set of teeth 33 formed on the left hand face of a collar 34fixed to the shaft I8 for rotation therewith by a set screw 36. Normallythe teeth 32 and 33 are not in engagement and the sleeve 24 and thecollar 28 are. held from rotating in a normal rest position by meanshereinafter described. The collars 28 and 34 comprise the driven anddriving members respectively'of the clutch employed to rotate thetransmitting sleeve 24, the. operation of which will be i more fullydescribed in the following paragraphs.

Whenever any one of the key levers I2 is actuated to initiate thetransmission of a group of representative code signals it causes theuniversal bail 31 pivotally mounted at 38 to pivot caps I3 arrangedsubstantially like those of an ordinary typewriter. Secured to the topof the base II and in spaced relation to one another are tworight-angled brackets I4 and I6 which support the transmittingmechanisms. Supported in the upper section of the bracket I4 is aflanged 22 is fixed for rotation therewith to the shaft 23 of aconstantly rotating electric motor (not shown) and, therefore, throughthe gears *2I and 22, the shaft I8 is adapted'to be continuouslyrotated.

Looselymounted on the left hand end thereof is a transmitting sleeve 24,Fig. 4, which has fixed thereon in predetermined arrangement a series oftransmitting .cams 26' intermediate with, spaces such as 21. Alsoloosely mounted upon the transmitting shaft :I8 to the right of thesleeve24 isa-collar 28 which is engaged with the sleeve 24 by means ofinterengaging tongues and grooves 29 and 3|, Fig.1, formed on and in thecollar 28 and the sleeve 24 respectively. The sleeve 24 is preventedfrom longitudinal movement along the shaft I8 while the collar 28 isfree to slide there along within predetermined limits. However, thecollar 281 is at all times engaged with the sleeve"'2 4'for rotationtherewith by means 'of the-tongues and shaft I8 adjacent the a. slightamount in a counter-clockwise direction. The upwardly extending arms ofthe universal bail has pivotally attached to it by shoulder screw 39 atrip lever4I The trip lever M is held against the stop 42 by an attachedspring 43 and has a hook 44. adjacent its right hand end which is inoperative relation with the depending arm of a three-armed lever 46. Thelever 46 is pivotally mounted on a shoulder screw 41 andtherightwardly'extending arm thereof has an eccentric screw 48 thereinwhich cooperates with the horizontal arm of the clutch throw-out leverThe clutch throw-out lever 49 is pivoted ona stud 5| extendinghorizontally from the bracket I6. The upper end of the substantiallyvertical arm of the throw-out lever 49' engages a side cam surface 52formed on the periphery of the collar 28 and normally holds the collarin its left hand position against the action of a compression spring 53coiled about the tongues and grooves 29 and 3|, tending to slide thecollar toward the right. Whenever thekey'lever I3 is actuated, it in thewell known manner through the instrumentalities of the universal bail31, the trip lever M and the'three-armed lever 46, causes the withdrawalof the end of the upwardlyextending arm of the clutch throw-outlever 49from engagement with the side cam surface 52. This operation of thethrow-out lever 49 allowst he spring 53 to slide the'collar 28 to therightto engage its teeth 32 with the teeth 33 on the collar 34 rotatingwith the shaft I8, whereupon'the collar-28 and the sleeve 24 startrotating." The trip lever 4| andthe three-armed lever'4B are arranged sothat after being operated, the clutch throw-out lever 49 is permitted toquickly return to its normal position where the upper end rides on theperiphery of the collar 28 in the path of the side cam surface 52to'cause disengagement 'of the teeth on the collar 28 with those on-thenot fully engaging is less than when such'clutches are employed onkeyboards capable of operating at speeds such as 500 character's perminute, where various factors such as the inertia ofthe moving elementsand the friction between-the transmitting shaft I8 and thetransmitting-sleeve sometimes prevents the clutch teeth from properlyengaging until after the driven "memberhas made apart of a revolution.The failure -of-a driven member such as the collar'28 maybe due to thetips-of the teeth-engaging sufiicientlyftogetherwith the frictionbetween the shaft and thesleeve, to rotate the sleeve for part ofarevolution before the tipsof the teeth slip past one another" tofmorefully engage the next tooth. Such slipping of the clutch members allowsthe driving member torotate relative to the driven member an amountequal to the distance between two'consec-utive teeth and as heretoforestated, l-engthen'the impulse being transmitted at this time anappreciable amount; During the first part of a revolution of thedriven'member the beveled surfaces of the teeth 32 and 33 may engagesumciently to rotate the driven member for part of a revolution beforethe engagement of the surfaces-parallel to' the axis of the shaft. Thisallows the driving member to rot'atea slight amount'relative to thedriven member until the parallel surfaces'do engage at some point in therotation of the driven member and lengthen the impulse being transmittedat that time. As will be hereinafer described the invention overcomesthese difficulties by preventing any .appreciable rotation of the drivenmember until at least. a substantialportion of the driving surfaces onthe teeth are properly engaged in overlapping relation and maintainingthe teeth in such proper engagement for substantially a completerevolution of the driven member.

In accordance with the invention a plate 56 is attached to the bracketl8 and the upper section 51 thereof, shown dotted in Fig. 1, is benthorizontally to form a mounting for an adjustable plate 58 adjustablysecured thereto by screws such as 59, Figs. 2 and 3. Pivotally mountedon the plate 58 by a shoulder screw 6| is a lever or detent 62 with anattached spring 63. The spring 63 is comparatively strong and holds thestraight end of the detent 62 in engagement with a stop 64 formed by aturned up section of the plate 58. The bent end 86 of the detent 62is inoperative relation with a flange 81 formed integral with the movableelement of the clutch or collar 28. The flange 61 has a radial slot ornotch 68 therein and in the normal rest position of the collar 28 thebent end 66 of the detent extends into the notch 68 an amount slightlyless than the distance the collar 28 moves to the right tohave its teeth32 fully engage the teeth 33 on the driven member or collar 34. If atthe start of a revolution of the collar 28 the driving surfaces of theteeth thereon do not have a substantial portion thereof engaged with thedriving surfaces of the teeth on the :driving member 34 or the collar 28has not slid to the right its proper amount, the leading radial edge ofthe notch in the flange 61 engages the beveled end of the detent 86 anddue to its rotative movement cams the collar 28 toward the right. If atthe time the leading edge of the notch 68 on the flange 81 engages thebeveled end 66 of the detent, the tips of the teeth or other than thedriving surfaces thereof are engaged, the detent will stop furtherrotation of the collar 28 until the driving surfaces of the teeth areengaged. Any delay thus caused in the rotation of the transmittingsleeve at this time does not affect the signals tobe transmitted duringthe rotation of the sleeve because during this time the rest impulse ofthe previous code group is being transmitted and its length onlydetermines the interval between code groups. When the teeth on thedriven and driving elements are properly engaged, the flange 61 is movedto the right sufficiently so that it just clears or is out of engagement with the end 88 0f the detent as shown in Fig. 3. During rotationof'the. collar 28 the end of the detent 66 is sufliciently close to theleft hand face of the flange 61 to prevent disengagement of the teeth 32and-33 until the notch'68 is again opposite the end of the detent at theend ofa revolution of the transmitting sleeve 24. Normally the spring 83attached to the detent-62 does not flex, it being provided to allow thedetent to pivot, should the clutch happen to jam for some reason. Thusthe driven member of a clutch ofthe above type, such as the collar 28,is held from rotating a substantial amount until the driving surfaces ofthe teeth engage whereupon they are fully engaged and are prevented frombeingdisengaged fonsubstantially the remainder ofthe revolution or untilthe end of the clutch throw-out lever 49 engages the side cam surface 52to cam the collar to the left to bring it to rest in its normal restposition, as shown in Fig. 2.

Asis apparent to those skilled in the art a n increase of the force ofthespring 53 tends to giv better engagement of the driven and drivingmembers 28 and 34; respectively. However,

such an arrangement does not insure full and proper engagement of thedriven and driving member on every operation, and in addition has thedisadvantage of requiring more force on the key-levers to actuate thethrow-out lever 49. By employing the detent 62, the force of the spring53 may be decreaseduntil it is just strong enough to start theengagement ofthe driven member with the driving member. Under suchconditions, the full and. proper engagement of the driven and drivingmembers is insured by the detent, and it prevents substantially allrotation of the driven member until the members are properly engaged. Anadditional advantage obtained by employing the detent is that with aweak spring 53 only a lightpressure is required It is obvious, ofcourse, that the invention may be applied to clutches other than thoseoperating in conjunction with keyboards and various modifications of theinvention may be made without departing from the spirit or essentialattributes thereof, and it is desired, therefore, that only suchlimitations shall be placed thereon as are imposed by the prior art orare specifically set forth in the appended claims.

What is claimed is:

1. In a clutch of the type described adapted to make one revolution at atime comprising a driving member and a driven member, engageablesurfaces on said driving and said driven members for rotating saiddriven member with said driving member on engagement thereof, resilientmeans for initiating the engagement of said engageable surfaces, meansfor completely engaging said engageable surfaces when initiated intoengagement by said resilient means, means on the keylevers to actuatethe throw-out lever w th sa d driv n .Inemb r .;mea s comprising the endof said detentanda side surface of said flan e; f rs 1p eve t ne d s n ame o s d driven and driving members during predetermined; portions ofeach revolutionof said driven member, a cam rotatablewithsaid drivenmember'and means including said cam for disengaging saiddrivenapddriving members after eac revolution of said driven member. s W v 3. Ina device of the type described, a normally irotating drivingmemberhaving teeth with driving surfaces disposed on one face thereof, a;normally at rest driven member, resilient 'meansfor moving said drivenmember axially to bring driving surfaces of teeth disposed on one facethereof into engagement with the driving surfaces of teeth on saiddriving member to be rotated thereby, a clutch throw-out lever, meansincluding said, clutch throw-out lever for preventing axial and rotativemovement of said driven member, means for voperating said clutchthrow-out lever to rendersaid resilient means effe'ctive to move saiddrivenmember to bring the teeth thereoninto engagement with the teeth onsaid driving member, means for preventing substantially all rotation ofsaid driven member until substantial engagement of, the driving surfacesof the teeth thereon with the driving sur faces of the teeth on saiddriving member, and means including said clutch throw-out lever fordisengaging the driving surfaces of said teeth after each revolution ofsaiddriven member.

4. In a device of the type described, a normally rotating driving memberhaving teeth with driving surfaces disposed on'one face thereof, anormally at rest driven member, resilient means for initiating themovement of said driven member axially to bring driving surfaces ofteeth disposed on one face thereof into engagement with thedrivingsurfaces of teeth on said driving member to be rotated thereby, athrow-out lever, means including said throw-out lever for preventingaxial and rotative movementof said driven member, means for operatingsaid throwout lever to render said resilient means effective to axiallymove said driven member, means for preventing substantially all rotationof said driven member until at least a portion of the driving surfacesof the teeth thereon are in engagement with the drivingsurfaces of theteeth on said driving member, means including said last-mentioned meansfor bringing the driving surfaces of said teeth into substantial fullengagement, and means for preventing disengagement of the drivingsurfaces of said teeth during substantially all the rotative movement ofsaid driven member. 1 ROLLINS WENTWOR'I'HJ' MAX U. DAVIS.

